Make debian bootstrapper more agnostic about venv packaging
Make debian bootstrapper more agnostic about venv packaging

Closes: #1061

stweil/letsencrypt,twstrike/le_for_patching,twstrike/le_for_patching,DavidGarciaCat/letsencrypt,mitnk/letsencrypt,jsha/letsencrypt,letsencrypt/letsencrypt,bsmr-misc-forks/letsencrypt,sjerdo/letsencrypt,goofwear/letsencrypt,VladimirTyrin/letsencrypt,lmcro/letsencrypt,thanatos/lets-encrypt-preview,ghyde/letsencrypt,martindale/letsencrypt,kuba/letsencrypt,VladimirTyrin/letsencrypt,brentdax/letsencrypt,ghyde/letsencrypt,TheBoegl/letsencrypt,lbeltrame/letsencrypt,jtl999/certbot,mitnk/letsencrypt,stweil/letsencrypt,kuba/letsencrypt,lbeltrame/letsencrypt,xgin/letsencrypt,hsduk/lets-encrypt-preview,jsha/letsencrypt,letsencrypt/letsencrypt,wteiken/letsencrypt,jtl999/certbot,hsduk/lets-encrypt-preview,TheBoegl/letsencrypt,martindale/letsencrypt,sjerdo/letsencrypt,dietsche/letsencrypt,thanatos/lets-encrypt-preview,dietsche/letsencrypt,Sveder/letsencrypt,bsmr-misc-forks/letsencrypt,piru/letsencrypt,mrb/letsencrypt,goofwear/letsencrypt,BillKeenan/lets-encrypt-preview,BillKeenan/lets-encrypt-preview,wteiken/letsencrypt,lmcro/letsencrypt,piru/letsencrypt,DavidGarciaCat/letsencrypt,mrb/letsencrypt,xgin/letsencrypt,Sveder/letsencrypt,brentdax/letsencrypt